Typewriting machine



May 30, 1939. R. G, THOMPSON TYPEWRITING MACHINE Filed Nov. 2e, 1935 www' Patented May 30, 1939 UNITED STATES TYPEWRITING MACHINE Russell G. Thompson, West Hartford, Conn., as-

signor to'Underwood Elliott Fisher Company, New York, N. Y., a corporation of Delaware Application November 26, 1935, Serial No. 51,557

10 Claims.

This invention relates to typewriting machines, and especially to devices'for supporting and securing such machines in a manner to reduce the noise resulting from their operation.

Much of the noise incident to the use of typewriting machines results from the magnification of the sounds of the operating mechanism by reason of the transmission of such sounds, in themselves small, through the machine-frame to the desk or working surface on which the machine rests, 'said surface acting as a sounding board, with a resulting magnifying effect.

Rubber or other resilient mountings, comprising cushions of various kinds and intended to l5 insulate against such transmission, are well known. The common characteristic of these prior devices, however, is that the resilient materia] is under compression, resulting in an obviously ineicient structure, because the immediate increase in density increases the sound and vibrationtransmission qualities of the material. In addition, the constant pounding to which a typewriter is subjected during use has the cumulative elect of so distorting and compacting the resilient material as to render it absolutely valueless as an insulator in a comparatively short time.

These disadvantages are overcome in the structures disclosed in this invention, in which the resilient material is placed under tension or shear,

thus lessening its density and increasing the insulating value, and continued use, up to a reasonable limit, acts actuallyto improve the inf sulating qualities.

In one form of this invention, rubber of suitable strength and density is vulcanized to load bearingmembers which are so assembled in the complete device as to present a novel, inverted bridge structure, on which the Weight of the mao chine is carried in suspension, the rubber acting as the 'suspending member, and being consequently subjected to a tensional stress.

In a second type disclosed herein, a rubber element of novel design isvulcanized to a centrally located metal post on which the weight of the machine is concentrated, andto a metal band which encircles the rubber element so as to prevent bulging or other lateral distortion thereof when -the load is applied. The lower portion of the rubber element is centrally counterbored, forming a cup-shaped base, with a comparatively narrow annular area in contact with the desk top. In this type of mounting, the weight of the machine subjects the rubber element to shear, or a combination of tension and shear, as the `centrally located downward thrust is opposed by the up' ward reaction of the annular area in contact with the desk top.

- -A novel hold-down device also disclosed herein,

utilizes the principle of rubber under tension to aiord a means of holding the machine firmly in contact with the desk top without presenting a channel through which shocks and sounds' of operation may reach the desk.

' 'I'he rubber element is vulcanized to an upper plate, having means for attaching to the machine, and to a lower plate, having a tapped hole to receive a headed screw, which may be inserted through the desk top from beneath. As this scr-ew isA tightened, the machine is pulled downward against the desk top, subjecting the rubber element to a tensional stress. f

These devices are novel in design and inexpensive to manufacture. They are readily applied to any typewriter by one unskilled in mechanics.

The outer surfaces are smooth, and the metal parts may be attractively plated or finished. Few recesses, which might accumulate dust, are presented.

Other features and advantages will hereinafter' appear.

In the accompanying drawing,

Figure 1 is a representation of a typewriter of the noiseless class, mounted on one type of resilient foot disclosed herein, and secured to a desk by a resilient hold-down device 'Figure 2 is a sectional view of a modified form of suspension type mounting.

Figure 3 is a substantially full-sized representation o' the mountings and hold-down device of Figure 1, partially in section, to show constructional details, and the deformation of the rubber under tensile stress.

Figure 4 is a modied form of mounting in which the rubber is subjected to shear by the` weight of the machine.

Figure illustrates the knurled surface of the load 'bearing post of Figure 4.

Figure 6 is a modification of the mounting device of the type illustrated in Figure 4.

Figure 7 is a partially sectional, disassembled view of the mounting of Figures 1 and 3.

Referring to Figure l, 20 represents a type- Writer of the noiseless class, with resilient feet or mountings 2| supporting said machine at the four corners thereof, and secured to a desk 22 by a resilient hold-down device 23.

'I'he feet 2|, Figures 3 and 7, are constructed with a resilient unit, designated bythe number 24, Figure 7, and comprising an annular rubber l:is

' ring 25, of suitalc'ble strength and density,- anA annular metaldisk `26 anda-plate 21, said plate 1 having secured thereto, or integral therewth,'a

post 28 'formed with a square cut gaging shoulder '29, and screw threaded extension 30. As illustrated in Figure '1 the inner diameter of annular ring 25 is greater than the diameter of post- 28,

as is also'thediameter of a centrally locatedhole 3| in.disk 2 6.I Disk 2 6 is formed with a concentric, downwardly 'turned'flanger32 of Y The rubber Vring 25 is secured, by'lvulcanization or other positive means, tn the'disk 26 and-the lower plate 21, thus forming the integrated, re-

silient unit 24.. 'Iheare'aof contactl o'f the rubber ring`25 with the :disk 26 may be so proportioned as to 'present a structure which, While 'resilient, is also suiliciently'resistant to side sway. to'

prevent the lateral vibrationf ofthe machinewhen in use. The possibilityl of noiseproducing conmet of the post z s with, the. disk 26 is preoluod' by this 'resistance to side sway, and the vspaced relation of post 2'8 with respect to disk.26.

'A cup 34, preferably -of brass or similar easily Worked material, is designedto receive the resilient. unit 24|."The inside' diameter of the cup is substantially equal'to the outer diametery f ange 32, to permit the wall Qof 'said flange to.

engage the inner wall'of cup 34 with a tight," frictional grip to prevent the'accidental separation of the cup and the resilient .unit which, when -v assembled, form the complete foot 2|. the upperedge of cup 34, andthe disk and4 cup thereby form a bridge structure from whichv the machine 20 may be resiliently suspended, subjecting/theA The shoulder 33 of disk. -26' rests on ring 25 to a tensional stress. The depthof cup 34 is 'greater than the total depth,4 of the resilient unit 24 when the :ring 25 is distorted under load., a's shown in Figure 3, and themachine, in eie'ct, floats in a rubber suspension.

' The cup 34, Figure '1, is provided with av'hole 35, 'and ispreferabiy fitted wana not .annular disk 36 of rubber, felt'or'sim'ilar material which prevents marringthe surface on which the ma- .chinerests and a'cts as 'anauxiliary 'shock and sound absorbing element.' The plate 21 is formed witha groove31 Ato receive a's'crewdriver'.

The assembled foot 2 i s easily attached to the `machine byv means of the threaded extension 3 0 for which a suitably tapped hole is provided in the machine base 38, Figures-1 and 3. lIfhe hole 35 in the bottom of cup 34 Vprovides access for a.

screwdriver. The shoulder 2 `ts as a positive gaging means to assure e correct alignment of the feet when secured to the machine.

I'he modification illustrated in Figure 2, end ploys similar construction, except that a heavier rubber-ring 40, of slightly diierent'design' than ring 25, -is vulcanized or otherwisesecured to the upper disk 26, lower plate 21, and also to the post k28 which maybe knurled to securely bondw-ith the rubber ring; A collar 4|, preferably integral' .with the ring 40, cushions the upper lportion of post 28 againsta chattering contact with 'the -edg'e of disk 26, and additionally'. prevents side sway. The modification of Figure 2 may be sub- .iectedto a heavierloa'd than the formpreviously described in. Figures 3 and 7,.because of the greater contactsurfaceor bond between the rubber and the metal parts.

A second'modication of the resilient foot 2| is shown at Figure 4, in which a central'metal post 42, preferably knurled, as shown in Figure 5,

having a comparatively large diameter 'gaging 'ward thrust resulting shoulder'. '43, and

eter substantially equal to that of shoulder 4 3.

The outer edge 4forms an annular base 41. A screw- 48, formed with a head-49 which may be .equal indiameter to that of-.shoulder 43, is in.

serted into a suitably tapped hole in post 4 2, and securely tightened therein. A n outerband 5|! a threaded extension. V44 by means of which'the foot may be secured to the..

machine, is inserted .into 'an annular rubber ring 45, which has a counterbored portion 4 6 of diam- I preferably ofbrass, and. with an inner diameter slightlyv smaller 'than' the ring-45,' is 4forced over The rubber ring 45, is Vthen bonded, preferably by vulcanizationfto the metaljpart's, forming th'e' complete resilient foot.

' In Figure 6', a simplified 4formof4 the device of. l l

'. said ringto'prevent the lateral distortion thereof when subjected-to the weight of the machine;4

'preferably knurled,formed at -one end with a' threaded extension'52 Vfor securing to -the ma chine base 38- and a' square'gaging .shoulder 53, 1 andat .the other end with a' screwdriver'slot 54,' is' inserted intoa'n annular rubber ring 55 h av'ing a counterbored lower. portion 56. 'A band5'1, similar .to ban'd chine is' centrally concentrated on' the rubber '25 50 of Figure"4, isv forced overthe f rubber ring, which is then vulcanized to the metal parts. ,Itwill be seen from Figure 4 .that lthe downfrom the woightof the. ma 3o ring 45, the loadfbearingsportion of-saidl-ri'ng be ing substantially a cylinder 4of di'amete'requal -to that' of the shoulder43 and the screw head 49.

-Thisdownward thrust Vis opposed .by the -upward .reaction' of `the areaof base 41zin; contact withl the desk 22. As thelateral deformation of the.

rubber is substantially prevented `by theband 50, and as the upper andlowerportions'oi the rubber-ring extend over the upper and lower edges of band 50, the compressionor" collaps'e o f' the ring 45 issubstanua11y1imited tothat portion thereof aboveand below the. band, and' the' re.

sult-ing stresswithinthe?. ring 45 is. largely shear,

localized in the .vertical plane of the innerwall of base 41, thus causing a .deformationof ring45 machine, beingconcentrated on the post .5|, is= -taken up by the rubber ring 55.-'by'reason`of the bond betwee'npost 5| and ring 5 5 resulting from the 'vulcanization thereof.' Ihe' comparatively large .diameter or the counterbored portionv 56 leaves only a.-'small bearings'urface 58, andthe .l

rubber ring` ,'55 is thus subjectedto a bending mo'- a'combination of tensional andshearing stresses,

cup-like 'forma-tion of the lower portion. results 'l in aneflicient, gripping contact, tending to p'rely secured to the working surface;

' vent thewalking" of the machine, if not rigidi l 70 In' the. hold-down device 23 illustrated in Figure 3, a block of rubber or lother resilient mate-" rial 60, having a centrally located recess '6| 1n the 4lower portion thereof,l is vulcanized to an upper plate 6 2 and alowerplate 63. Plate 621s. formed sneden? with a gaging shoulder 8l and a screw-threaded Vextension 65 by means of whichthe device may be secured to the machine frame 38, as shown in Figures 1 and 3. Plate 63 has a tapped boss 86 to receive a suitable headed screw 61.

When the machine 20 is equipped with the resilient mountings 2|, of any of the forms described herein, and the fastening devices 2l, it can be firmly secured to the desk 22, by passing the screw 61 .through a suitable hole in the desk top, and inserting it in the tapped boss 66, whereupon, when screw 61 is tightened, the machine will be firmly brought down on the feet 2|. .The rubber block 6U of fastener 23 will be subjected to ,a tensile stress, causing the block to take the distorted shape illustrated in Figure 3. The expansion of the rubber lessens its density, and effectively insulates against the transmission of shocks and sounds to the desk top.

Preferably, two hold-down devices are used, one on each side of the machine, and centrally located with respect to the mountings 2 I.

Variations may be resorted to within the scope of the invention, and portions vof the improvements may be used without others.

Having thus described my invention, I claim:

1. A shock and sound absorbing mounting for a typewriter, comprising a resilient annular ring, a stud, threaded for attachment to said typewriter, centrally disposed in said annular ring and having a comparatively largediameterhead Y f per surface of said ring, and a cup arranged to receive said annular ring and to act as a base by co-operating with a turned flange at the periphery of said annular disk.

2. For use with a typewriting machine, a shock and sound absorbing mounting comprising the combination of a substantially cylindrical structure carried on a protective member of resilient material, an annular disk bridging the upper end of said structure, and a stud, for attaching to the typewriter, projecting through said disk and suspending therefrom by an interponent resilient annular ring secured to said stud and said disk, said annular ring thereby insulating against the transmission of shocks and sounds by carrying the weight of said typewriter in resilient suspension from said disk, and said protective member acting as an auxiliary shock and sound absorbing base.

3. A resilient foot for a typewriter, comprising a hollow base, a member bridgingsaid base, a headed stud extending through and beneath the bridge-member in spaced relation thereto, said stud having means for attachment with said typewriter, a ring of resilient material interposed between and secured to said bridge-member and said stud, so that the weight of the typewriter will place said resilient material under tension, and a cushioning collar interposed between said stud and said bridge-member, so as to dampen sideward movement and prevent, chattering contact.

4. A non-resonant mounting for a typewriter, comprising a stud attachable to a typewriter to depend therefrom and-having an annular shoulderprojecting normally from said stud, a disk having an aperture admitting said stud and disposed to overlie said annular shoulder in parallelism therewith, means for detachably supporting said disk, said means presenting guide surfaces adjacent the periphery of said shoulder to limit lateral movement of said stud, and a resilient ring embracing said stud and interposed between said shoulder and said disk for tensioning in a vertical direction only by the load'of the typewriter.

5. A non-resonant mounting ifor a typewriter, comprising a stud attachable to a typewriter to depend therefrom and having an annular shoulder projecting at right angles from said stud, a base having upstanding walls closely surrounding the periphery of said shoulder to guide same and having a. disk closely surrounding said stud and disposed to overlie the annular shoulder of said stud in parallelism therewith, and a resilient ring embracing said stud and interposed between said shoulder and said disk for tensioning in a vertical direction only by the load of the typewriter. 1

6. A non-resonant mounting for atypewriter, comprising a stud attachable to a typewriter to depend therefrom and having an annular shoulder projecting normally from sa'id stud, a disk having an aperture closely surrounding said stud and disposed to overlie the annular shoulder of said stud in parallelism therewith, means for supporting said disk, a resilient ring embracing said stud and interposed between said shoulder and said disk for tensioning in a vertical direction by the load of the typewriter, and a resilient collar lining the aperture of said disk to cushion said stud against lateral movement.

7. A non-resonant mounting for a typewriter, comprising a stud for threadedl engaging a typewriter to depend therefrom a d having an annular shoulder projecting normally from the axis of said stud, a cylindrical cup having side walls adjacent the periphery of said shoulder to limit lateral movement of said stud, a disk superposed on said cup and surrounding said stud to overlie the annular shoulder thereof, and a resilient ring interposed between said shoulder and said `disk for tensioning in a vertical direction by the load of the typewriter, said cup having a substantially closed bottom portion dening an aperture for access to said stud in installing the composite mounting on a typewriter.

8. A non-resonant mounting for a typewriter, comprisinga stud attachable tofa typewriter to depend therefrom and having an annular shoulder projecting normally from said stud, a cuplike housing presenting upstanding side walls disposed adjacent the periphery of said shoulder to limit lateral movement of said stud and terminating in a rim, a disk having releasable engagement with said cup rim for assembly, and overlying said shoulder in parallelism therewith,

and a resilient ring secured to said disk and shoulder for yieldable support of the typewriter on said stud.-

9. Means for holding a typewriter in oating suspension on a platform for isolation of sound .vibrations within the typewriter, said holding means comprising a plurality of units for co1- lectively suspending theload of the typewriter on the platform, each of said units including a resilient member tensioned by the load of the typewriter, and a resilient element interposed between the typewriter and platform intermediate said units and stressed in tension, whereby said element may tend to further tension the resilient elements of said units to coactively isolate sound vibrtions of the typewriter from transmission to the platform.

10. Means for holding a typewriter in floating suspension on a platform for isolation of sound vibrations within the typewriter, said holding means comprising a plurality of units for co1- lectively suspending the load of the typewriter on the platform, each of said units including a resilient member tensioned by the load of the typewriter, and a resilient element consisting of a block of rubber interposed between the type- L Writer and platform intermediate said units and stressed in tension, whereby said element may tend to further tension the resilient elements of said units to coactively isolate sound vibrations of the typewriter from transmission to the platform. 1

- RUSSELL G. THOMPSQ 

